Tandem white OLEDs (organic light emitting diodes) have advantages such as high efficiency, no need of fine metal mask (FMM) or other complex patterning processes, capability of mass production and realizing a full color display. Thus, the tandem white OLEDs have a wide application prospect and have drawn extensive attention.
However, applying a plurality of (for example, two or three) kinds of light emitting materials in a same component results in some problems. One micro-resonant optical cavity in one component has only one resonant cavity length; it is difficult to optimize a plurality of kinds of light emitting layers, especially in the case of a big angle of view, which results in color drift at different angle of views in the device applying tandem white OLEDs. Especially for the structure applying more than three light emitting layers, for instance, the structure applying B/Y/B (blue/yellow/blue) light emitting layers, in the case of a big angle of view, the light emitting layer far from the reflective plane is prone to suffer from large color drift because of the change of optical interference condition. Thus, the device shows an obvious color drift, and even through the structure has been optimized, the color drift can not be avoided, and thus there is great difference between the color temperature in a front view and the color temperature in a side view.